public static void RenderText(string message, float x, float y, float scale, float rotation, Color color)
{
// Apply the 2D orthographic matrix transformation
SetOrthographicMatrix();
rotation = rotation * 180f / Constants.pi_float;
// Set the text shader program and pass in the color as a parameter
GL.UseProgram(ShaderManager.TextShader.GpuHandle);
int uniformLocation = GL.GetUniformLocation(ShaderManager.TextShader.GpuHandle, "color");
GL.Uniform4(uniformLocation, new Color4(color.R / 255f, color.G / 255f, color.B / 255f, color.A / 255f));
// Apply the model view matrix transformations
GL.MatrixMode(MatrixMode.Modelview);
GL.LoadIdentity();
GL.Translate((x * _screenWidth - _screenWidth / 2f), (y * _screenHeight - _screenHeight / 2f), 0f);
if (rotation != 0)
{
GL.Rotate(rotation, 0, 0, 1);
}
// Set up the verteces (hardware instanced for all character sprites)
GL.BindBuffer(BufferTarget.ArrayBuffer, CharacterSprite.GpuVertexBufferHandle);
GL.VertexPointer(3, VertexPointerType.Float, 0, IntPtr.Zero);
GL.EnableClientState(ArrayCap.VertexArray);
// this standardizes the size (not depedent on sprite sheet size)
float sizeRatio = scale / (float)_font.LineHeight;
for (int i = 0; i < message.Length; i++)
{
CharacterSprite sprite = _font.Get(message[i]);
// Calculate the per-character transformational values
float ySize = sizeRatio * (float)sprite.OriginalHeight;
float yOffset = sizeRatio * (float)sprite.YOffset;
float xSize = sizeRatio * (float)sprite.OriginalWidth;
float xRatio = xSize / (float)(sprite.OriginalWidth);
float xOffset = xRatio * (float)sprite.XOffset;
float xAdvance = xRatio * (float)sprite.XAdvance;
// Kearning (extra adjustments between specific charasters)
if (i + 1 < message.Length)
{
xAdvance += xRatio * (float)sprite.CheckKearning(message[i + 1]);
}
// Apply the character offsets and scaling
GL.Translate(xOffset, -yOffset, 0f);
GL.Scale(xSize, ySize, 0f);
// Bind the texture and set up the texture coordinates
GL.BindTexture(TextureTarget.Texture2D, sprite.Texture.GpuHandle);
GL.BindBuffer(BufferTarget.ArrayBuffer, sprite.GPUTextureCoordinateBufferHandle);
GL.TexCoordPointer(2, TexCoordPointerType.Float, 0, IntPtr.Zero);
GL.EnableClientState(ArrayCap.TextureCoordArray);
// Perform the render
//GL.DrawArrays(PrimitiveType.Triangles, 0, sprite.VertexCount);
GL.DrawArrays(BeginMode.Triangles, 0, sprite.VertexCount);
// Remove the per character transforms and advance to the next charachers position
GL.Scale(1 / xSize, 1 / ySize, 0f);
GL.Translate(-xOffset + xAdvance, yOffset, 0f);
}
}
